In the US, gay men have been banned from donating blood since 1983, during the height of the Aids scare.
The ban remains in place, although it has long been argued there is no scientific basis for it. The Obama administration has introduced some small changes to the law - for example, that gay and bi men can donate if they have been celibate for a year.
Lines at blood clinics snaked around whole blocks in Orlando following Sunday's massacre of 49 people at a local gay nightclub - which is just as well, because their help was desperately needed at local hospitals.
The Isis-inspired attack has left people fearful of a backlash against normal Muslim citizens, as has sadly been the case in so many other recent terror attacks.
But one Orlando local has been disproving all the stereotypes about faith and gay rights being incompatible - by donating blood while he was fasting for Ramadan.
Mahmoud El-Awadi wrote about the experience on his Facebook page - which has been shared more than 200,000 times. Reposts on other social media networks mean his gesture has reached hundreds of thousands more people.
Yes I donated blood even though I can't eat or drink anything cause I'm fasting in our holy month Ramadan just like hundreds of other Muslims who donated here in Orlando.
Yes I'm angry for what happened last night and all the innocent lives lost.
I'm sad, frustrated and mad that a crazy guy claimed to be a Muslim did that shameful act.
Yes our blood all looks the same so get out there and donate blood cause our fellow American citizens are injured.